Super-additivity of quantum capacity in simple channels

Zhen Wu; Qi Zhao; Zhihao Ma

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arXiv · 2505.24661

Super-additivity of quantum capacity in simple channels

Zhen Wu·Qi Zhao·Zhihao Ma

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Abstract

The super-additivity of quantum channel capacity is an important feature of quantum information theory different from classical theory, which has been attracting attention. Recently a special channel called ``platypus channel'' exhibits super-additive quantum capacity when combined with qudit erasure channels. Here we consider the ``generalized platypus channel'', prove that it has computable channel capacities, such as both private and classical capacity equal to $1$, and in particular, the generalized platypus channel still displays the super-additivity of quantum capacity when combined with qudit erasure channels and multilevel amplitude damping channels respectively.

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Zhen Wu, Qi Zhao, Zhihao Ma. 2025-05-30. Super-additivity of quantum capacity in simple channels. https://arxiv.org/abs/2505.24661

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